Exploring Influenza Vaccination Demand among Elderly Population in Taiwan

by Liu, Chi-mei

Abstract (Summary)

Research Objectives :
Studies indicated that influenza vaccination is a cost-effective clinical prevention for elderly persons. Higher influenza vaccination rate will reduce disease threat and related health care utilizations in a health care system. From 2001, Taiwan provided free influenza vaccine for all of its elderly persons. Nevertheless, the influenza vaccination rate was lower than the expected goal and less than 50%. Therefore, this study aims to evaluate the key factors which affect elderly persons receiving influenza vaccination in Taiwan.
Study Design :
This is a retrospective study using national representative data from year 2000 to 2004. The vaccination information was linked with outpatient and inpatient records in individual level. The data was also linked with medical institution¡¦s characteristics. We modified Health Belief Model and threat-responsiveness theory to hypothesize previous experiences on vaccination and medical utilization were important factors affecting individual¡¦ s probability of receiving influenza vaccination. Population-based descriptive analysis was conducted to assess the demography characteristics, health status, and health care utilizations. We tested the significance by t-test and Chi-Square test. Moreover, we applied multivariate logistic regression to analyze the associations between controlled factors and the probability of receiving influenza vaccination.
Population Studied :
People aged 65 years and older were drawn from Taiwan¡¦s national health insurance database from 2000 to 2004. The total sample size is 23,023 elderly persons.
Principle Finding:
The study results indicated that the most important factor affect elderly persons continue to receive influenza vaccination is whether the person had received influenza vaccination during last flu season or not. Elderly persons who had received influenza vaccination in last flu season were significantly seven times more likely to receive influenza vaccination in this year (OR: 7.66 [95%CI:7.34-8.00]). Other key affecting factors include age, health status, flu-related inpatient and outpatient utilizations in last year, locations of receiving influenza vaccination, and the health care organizations¡¦ levels.
Conclusion :
This research combines Health Belief Model and threat-responsiveness theory as framework to analyze the national dataset of four year¡¦s elderly influenza vaccination rate change in Taiwan. We found that lagged effects such as vaccination status and flu-related health care use in previous flu season significantly affect the volition of influenza vaccination. Therefore, further research on how to adopt this critical finding and promote higher vaccination rate are in great needs.
Implications for Policy, Delivery or Practice:
Free coverage and easy access does not guarantee high influenza vaccination rate in Taiwan, even it is under universal health insurance program. This study provides empirical investigations on key factors that might affect the elderly persons¡¦ intention to receive influenza vaccination. Elderly persons¡¦ responses to regular clinical prevention and disease threat were positively associated with probability of having influenza vaccination. By focusing on the major factors and conducting related promotion programs, effective prevention policy can be reinforced. Moreover, this study result could serve as valuable reference for other countries which also has or plans to have free influenza vaccination policy, particularly for those countries also with national health insurance program.